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Analog Devices Inc. ADM691ARZ-REEL
- Part No.:
- ADM691ARZ-REEL
- Manufacturer:
- Analog Devices Inc.
- Category:
- Supervisors
- Package:
- 16-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
ADM691ARZ-REEL.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,305
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Product details
Overview
ADM691ARZ-REEL from Analog Devices is a microprocessor supervisory circuit providing power-on reset, battery backup switchover, watchdog timer, chip enable gating, and power-fail warning in a single 16-pin SOIC package. It features a 4.65 V ±3% reset threshold, 200 ms fixed reset timeout (adjustable), 1.6 s/100 ms selectable watchdog timeout, and supports VCC as low as 1 V during reset assertion. It is used in industrial controllers and embedded systems requiring reliable power monitoring and RAM write protection.
For engineers reviewing the ADM691ARZ-REEL datasheet, ADM691ARZ-REEL pinout, ADM691ARZ-REEL application, or ADM691ARZ-REEL equivalent, this page delivers verified functional specifications, validated pin roles, confirmed battery switchover behavior, real-world timing constraints (e.g., 80 µs RESET delay, 6 ns CE propagation), and precise alternative part comparisons - all grounded in Analog Devices' official ADM691A/ADM693A/ADM800L/M Rev. 0 documentation.
Technical Context
The ADM691ARZ-REEL integrates a precision 4.65 V voltage detector with 15 mV hysteresis, an internal oscillator enabling fixed 200 ms reset and 1.6 s watchdog timeout (or 100 ms short period when OSC IN is grounded), and dual-mode battery switchover: VCC-to-VOUT via 0.75 Ω PMOS switch (250 mA max), VBATT-to-VOUT via 7 Ω MOSFET (5 mA typical backup current). Its CE gating logic forces CEOUT high during reset, preventing RAM writes under invalid VCC.
It includes a 1.25 V power-fail comparator (PFI/PFO) with 25 µs response, WDI three-level input supporting watchdog disable via floating, and open-drain RESET/RESET outputs with guaranteed low-voltage operation down to VCC = 1 V. All logic operates across –40°C to +85°C with <100 µA supply current in normal mode and 0.04 µA in battery backup.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65 V ±3% - ensures compatibility with +5 V ±5% supplies and prevents premature reset assertion during nominal operation. |
| Reset Timeout | 200 ms typ - holds microprocessor in reset long enough for power supply and clock stabilization after power-up. |
| Watchdog Timeout | 1.6 s (long) or 100 ms (short) - configurable via OSC IN/OSC SEL to match software execution cycle margins. |
| VCC-to-VOUT On-Resistance | 0.75 Ω typ - enables up to 250 mA output with <188 mV dropout at 250 mA, suitable for direct CMOS RAM supply. |
| Battery Backup Current | 0.04 µA typ - minimizes drain on backup batteries or supercapacitors during extended power loss. |
| PFI Comparator Threshold | 1.25 V - allows early power-fail detection using external resistor divider, triggering NMI before VCC drops below reset level. |
| CEIN-to-CEOUT Propagation Delay | 6 ns typ - ensures tight timing alignment between processor CE and memory access during valid VCC windows. |
Pinout & Package
ADM691ARZ-REEL is housed in a 16-pin narrow SOIC (R-16N) package per Analog Devices' ordering guide. Pin functions are electrically validated and mapped as follows:
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 VBATT | Backup battery input | Connects to external battery/capacitor; enables automatic switchover when VCC falls below reset threshold. |
| 2 VOUT | Switched output | Delivers either VCC (via 0.75 Ω PMOS) or VBATT (via 7 Ω MOSFET) depending on supply status and threshold comparison. |
| 3 VCC | Main power supply input | +5 V supply rail monitored for reset generation; functional down to 1 V during brownout. |
| 4 GND | Ground reference | Common return for all analog and digital circuitry; required for accurate voltage detection and comparator operation. |
| 5 BATT ON | Battery switchover status output | Logic-high when VBATT powers VOUT; drives base of external PNP transistor to boost VOUT current beyond 250 mA. |
| 6 LOW LINE | Low VCC indicator | Asserts low immediately when VCC drops below 4.65 V; used for system status signaling or interrupt generation. |
| 7 OSC IN | Oscillator control input | Selects watchdog/reset timing: grounded = 100 ms short timeout; floating = 1.6 s long timeout; capacitor-driven = adjustable period. |
| 8 OSC SEL | Oscillator mode select | Floating/high = internal oscillator active; grounded = external clock or capacitor mode enabled. |
| 9 PFI | Power fail input | Non-inverting input to 1.25 V comparator; monitors divided-down supply voltage for early power-loss warning. |
| 10 PFO | Power fail output | Open-drain output that pulls low when PFI < 1.25 V; typically connected to µP NMI for data save routines. |
| 11 WDI | Watchdog input | Three-level input (low/mid/high); toggling resets watchdog timer; floating disables watchdog function. |
| 12 CEOUT | Gated chip enable output | Follows CEIN when VCC > reset threshold; forced high during reset to block RAM writes under invalid supply. |
| 13 CEIN | Chip enable input | Directly controls CEOUT; tied to GND/VOUT if unused to prevent floating inputs. |
| 14 WDO | Watchdog status output | Asserts low on watchdog timeout; returns high on next WDI transition; remains high if WDI is unconnected. |
| 15 RESET | Active-low reset output | Drives µP reset pin low during power-up, brownout, or watchdog timeout; guaranteed operation down to VCC = 1 V. |
| 16 RESET | Active-high reset output | Complementary open-drain output; provides active-high reset signal for processors requiring inverted reset polarity. |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable reset & watchdog timing | Supports fixed 200 ms/1.6 s, 100 ms short, or user-defined periods via external capacitor (C = 47 pF → 200 ms reset) or clock (fCLK = 100 kHz → 20.48 ms reset). |
| Low-power battery backup mode | Draws only 0.04 µA from VBATT while maintaining VOUT connection and RESET assertion - extends 3 V lithium battery life to >10 years. |
| Robust CE gating logic | Forces CEOUT high within 15 µs of RESET assertion, eliminating risk of corrupted RAM writes during power transitions. |
| Early power-fail warning | 1.25 V PFI comparator with 25 µs response enables ≥10 ms advance warning before VCC crosses 4.65 V reset threshold. |
| Wide VCC operating range | Functions with VCC as low as 1 V during brownout - ensures deterministic reset hold until supply recovers or battery takes over. |
Applications
| Industrial Controller Power Monitoring | Automotive Infotainment Memory Backup |
|---|---|
Use Scenario: Monitoring 5 V supply rails in programmable logic controllers subjected to voltage sags and EMI-induced transients. IC Role / Device Role / Timing Role: ADM691ARZ-REEL acts as primary power supervisor - asserting RESET on VCC drop below 4.65 V, enabling battery-backed SRAM retention via VOUT, and gating CE to prevent write corruption. Use Value: Guarantees deterministic controller restart after brownout and preserves configuration data without external supervision circuitry. |
Use Scenario: Maintaining volatile settings and calibration data in head-unit systems during engine cranking (VCC dip to 6–7 V). IC Role / Device Role / Timing Role: ADM691ARZ-REEL switches VOUT to VBATT upon VCC fall, asserts LOW LINE to trigger firmware save routine, and uses PFO to generate NMI interrupt before main supply collapse. Use Value: Enables zero-data-loss shutdown sequence with <100 µs PFI→PFO latency and <200 ms RESET hold time for safe EEPROM write completion. |
| Medical Device Power Sequencing | Point-of-Sale Terminal Battery Switchover |
Use Scenario: Ensuring safe power-up sequencing and fault recovery in portable diagnostic equipment with dual-supply architecture. IC Role / Device Role / Timing Role: ADM691ARZ-REEL provides synchronized reset to MCU and analog front-end, monitors auxiliary 3.3 V rail via PFI divider, and gates CE to isolate flash memory during unstable VCC. Use Value: Eliminates race conditions during multi-rail power-up and meets IEC 62304 Class C requirements for deterministic fault response. |
Use Scenario: Supporting uninterrupted transaction logging in retail terminals using coin-cell backup during AC power loss. IC Role / Device Role / Timing Role: ADM691ARZ-REEL detects VCC failure, switches VOUT to 3 V coin cell, asserts RESET to halt CPU, and maintains CEOUT high to lock RAM until backup power stabilizes. Use Value: Achieves <5 µA total system standby current in battery mode and sustains 250 mA peak RAM access current via internal PMOS switch. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX691ACPE+ | Pin-compatible 16-pin DIP; identical 4.65 V reset threshold and 200 ms timeout but lacks adjustable watchdog and has higher 250 µA quiescent current. | Preferred for legacy through-hole designs; not suitable for space-constrained SOIC layouts or ultra-low-power battery backup. | Select MAX691ACPE+ only when DIP footprint and backward compatibility with Maxim-based schematics are mandatory. |
| TPS3823MPW | Single-channel 3.3 V supervisor (reset threshold 2.93 V); no battery switchover, no CE gating, no watchdog - only basic reset generation. | Applicable only for simple reset-only use cases; cannot replace ADM691ARZ-REEL in systems requiring RAM backup or watchdog functionality. | Choose TPS3823MPW solely for cost-sensitive 3.3 V systems where full supervisory features are unnecessary. |
Compared with MAX691ACPE+, ADM691ARZ-REEL offers SOIC packaging, lower 100 µA supply current, and configurable watchdog timing; compared with TPS3823MPW, it delivers integrated battery switchover, CE gating, and dual reset outputs - making it the only viable option for complete 5 V microprocessor supervision with memory protection.
Availability
ADM691ARZ-REEL is available at Aetrix Electronics and suitable for industrial controllers, automotive infotainment systems, and medical diagnostic devices requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for ADM691ARZ-REEL includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Analog Devices is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets since 1965.
The ADM691A family was designed specifically for robust microprocessor power supervision in harsh environments - integrating reset, watchdog, battery switchover, CE gating, and power-fail warning into one IC to eliminate discrete supervision circuitry in embedded systems.
FAQ
What is the reset threshold voltage of the ADM691ARZ-REEL?
The ADM691ARZ-REEL has a guaranteed reset threshold of 4.65 V ±3%, with minimum and maximum limits of 4.5 V and 4.75 V respectively. This threshold is optimized for +5 V ±5% power supplies and remains functional even when VCC drops as low as 1 V during brownout conditions, ensuring reliable reset assertion across wide operating margins.
Does the ADM691ARZ-REEL support adjustable watchdog timeout periods?
Yes, the ADM691ARZ-REEL supports adjustable watchdog timeout via OSC IN and OSC SEL pins. With OSC SEL grounded, connecting a capacitor (e.g., 47 pF) from OSC IN to GND yields a 1.6 s timeout; scaling capacitance linearly adjusts timeout (Twd = 600 × C/47 ms). An external clock applied to OSC IN sets timeout as Twd = 1024/fCLK, enabling precise synchronization to system timing requirements.
How does the ADM691ARZ-REEL handle battery backup switching?
The ADM691ARZ-REEL automatically switches VOUT between VCC and VBATT based on voltage comparison and reset threshold crossing. During normal operation, VCC is routed to VOUT through a 0.75 Ω PMOS switch (250 mA capable); during power loss, VBATT connects via a 7 Ω MOSFET with <0.15 V dropout at 5 mA. Battery standby current is just 0.04 µA, preserving backup energy for years.
Can the ADM691ARZ-REEL be used with 3.3 V microprocessors?
No - the ADM691ARZ-REEL is specified for 4.75 V to 5.5 V VCC operation and features a 4.65 V reset threshold incompatible with 3.3 V logic. For 3.3 V systems, Analog Devices offers the ADM692A (3.08 V threshold) or consider the TPS3808G18 - but neither provides the full feature set (battery switchover, CE gating, PFI/PFO) of the ADM691ARZ-REEL.
What is the purpose of the dual RESET and RESET outputs on the ADM691ARZ-REEL?
The ADM691ARZ-REEL provides both active-low RESET (pin 15) and active-high RESET (pin 16) to accommodate microprocessors with differing reset polarity requirements. RESET is push-pull capable (3.5 V high, 0.4 V low at 3.2 mA), while RESET is open-drain - allowing flexible interfacing with 5 V, 3.3 V, or mixed-voltage systems via external pull-up resistors.
ADM691ARZ-REEL Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Battery Backup Circuit
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 4.65V
- Output:
- Open Drain, Push-Pull
- Reset:
- Active High/Active Low
- Reset Timeout:
- 35ms Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
ADM691ARZ-REEL FAQ
1.How can I place an order for ADM691ARZ-REEL through Aetrix?
Please submit a Request for Quotation (RFQ) for ADM691ARZ-REEL on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for ADM691ARZ-REEL reliable?
The price and inventory of ADM691ARZ-REEL are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ADM691ARZ-REEL is usually 5 days.
3.What payment methods are accepted for ADM691ARZ-REEL?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ADM691ARZ-REEL transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ADM691ARZ-REEL?
ADM691ARZ-REEL orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ADM691ARZ-REEL order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for ADM691ARZ-REEL?
For technical support, including ADM691ARZ-REEL datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ADM691ARZ-REEL requirements.
6.How does Aetrix verify that ADM691ARZ-REEL is sourced from the original manufacturer or authorized distributors?
All ADM691ARZ-REEL products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that ADM691ARZ-REEL meets industry standards.
7.What is the process for return or replacement of ADM691ARZ-REEL?
All ADM691ARZ-REEL units undergo pre-shipment inspection (PSI). If there is an issue with ADM691ARZ-REEL, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The ADM691ARZ-REEL part is unused and in its original packaging.
Return procedure for ADM691ARZ-REEL:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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